Herb
Pennyroyal
A pungent mint-family herb traditionally used externally against mites and fleas.
🛑 RemedyRank warns against this
Pennyroyal oil has killed people. Even small amounts can cause fatal liver failure, and it has been used to try to end pregnancies with tragic results.
This page exists so the reasons are written down plainly, not because the practice is recommended. Nothing is sold here. If a doctor has prescribed something for a diagnosed condition, follow their guidance — that is a decision between you and them, and it is a different thing from trying this at home.
⤢📊 How it ranks (our editor score) — 45/100Tap to see the breakdown
🌱 What it is
Pennyroyal is a strong-smelling herb in the mint family, historically used as an insect repellent and topical wash.
📜 Where it comes from
Pennyroyal was known to Greco-Roman physicians, with Dioscorides describing its uses in classical antiquity, and it continued through medieval European herbals as a pungent household herb. Its strong scent led to a long folk tradition of using it externally as an insect repellent against fleas and mites, a practice that carried into early American household remedies.
🥄 How to use it
Apply a cooled, strongly steeped teaA warm drink made by steeping herbs in hot water. How to make a tea → directly to the affected skin as a wash; do not use the essential oilA very concentrated plant oil — always diluted before it touches skin. How to make an essential oil →.
How much: External wash only, applied 1-2 times daily as needed; never ingest.
Why it works: Pennyroyal's aromatic compounds are believed to repel and help kill mites, reducing itching and irritation.
⚠️ Cautions
- Never take pennyroyal oil internally — even small amounts of the essential oil are toxic and can cause liver failure.
- Avoid entirely during pregnancy, as it can stimulate the uterus and has caused miscarriage.
- Use only as a dilute external tea wash; discontinue if skin irritation occurs.
📚 Learn more
🌿 Deeper natural detail
🩺 The conventional view
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📚 Resource confidence
Based on mentions in health references
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